In dental implantology, it is well-known to use for the drilling of bores as implant beds, a set of drills comprising bud bur, pilot bur and helical bur. Such a set of burs is manufactured, for instance, by the company Institut Straumann AG, Basel, Switzerland.
In practice, the procedure in drilling a bore as an implant bed is as follows. First, the exposed bone surface is smoothed with a bud bur and the implant site is marked with the bud bur and possibly enlarged, bud burs with increasing diameters being used in the latter case. Subsequently, the implant bed is prepared with a suitable pilot bur for determining the bore axis. In a final step, the implant bed is then drilled to the final necessary width using a suitable helical bur.
With the above procedure, however, drilling with the helical bur causes a rattle or deflection due to the cutting edges of the helical bur engaging with or being caught in the edge of the former smaller bore. This leads to the above-mentioned rattle or deflection of the helical bur.
Up to this now, this problem was solved by slightly chamfering the edges of the smaller bore with a profiling cutter before drilling with the helical bur. This solution, however, has the disadvantage of requiring an additional tool, i.e. a profiling cutter, and a corresponding working step.
Accordingly, in case of renewed boring to a larger diameter, an additional profiling cutter and working step would be necessary.
An alternative to the above solution is offered by WO 2004/080325 A1, wherein a pilot guide with smaller diameter is integrated in the tip of the helical bur. The smaller diameter of the pilot guide corresponds to the diameter of the previous pilot bur or pilot bore, respectively, and is used for better guidance of the helical bur.
The alternative of WO 2004/080325 A1 is not satisfactory insofar as it ablates unnecessary bone material at the pilot guide, a superfluous blind hole being formed apically in the implant bed which is not necessary for receiving the dental implant and is detrimental to osteointegration and implant healing. This disadvantage can be remedied by an appropriate design of the bore length and by the provision of an additional bur for ablation of the bone tissue in the area of the pilot guide, but this leads, in turn, to the problem of an additional tool and an additional working step.